16k: Add 16K variant kernel/ramdisk build targets

This adds two new build variables, BOARD_KERNEL_PATH_16K and
BOARD_KERNEL_MODULES_16K . BOARD_KERNEL_PATH_16K will be copied
to output directory as is.

BOARD_KERNEL_MODULES_16K is a list of modules which will be packed into a
ramdisk and added to output dir. This allows cuttlefish to switch to 16K
kernel at runtime without adding too much overhead, as ramdisk building
takes very little time.

Bug: 253827893
Test: m kernel_16k ramdisk_16k

Change-Id: Ibb36ba4c3399b3f193795aea6597a4aa535f1bec
diff --git a/core/main.mk b/core/main.mk
index cb4dca6..a747967 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1810,6 +1810,8 @@
     $(INTERNAL_OTA_PACKAGE_TARGET) \
     $(INTERNAL_OTA_METADATA) \
     $(INTERNAL_OTA_PARTIAL_PACKAGE_TARGET) \
+    $(BUILT_RAMDISK_16K_TARGET) \
+    $(BUILT_KERNEL_16K_TARGET) \
     $(INTERNAL_OTA_RETROFIT_DYNAMIC_PARTITIONS_PACKAGE_TARGET) \
     $(SYMBOLS_ZIP) \
     $(SYMBOLS_MAPPING) \